Lines of Position GC Sailing

Chart Work - Traditional paper chart work on an ECS.

the three types of lines of position used are:

• Bearing
• Range
• Horizontal angle

Fix by three simultaneous bearings.

Offshore navigators use celestial navigation,sextant observations, as a backup for the GPS. Use a sextant for taking the altitude of a celestial body and OpenCPN to plot the celestial circle of position instead the LoP -Line of Position-. Repeat this and take at least three sights. You easily can check if any danger is near your fix, and the uncertainty in your position.

Parameters of a circle of position in astronavigation.

• Method explained

• Rhumb Line. Direct with OpenCPN (And also using Plugin Route_pi).
• Great Circle(Direct in OpenCPN using using Plugin Route_pi).
• Composite(Direct in OpenCPN using using Plugin Route_pi).

The three types of sailing are also available in ChartWork

Composite Route.

Composite Route plot with OpenCPN.

RDF or radiogoniometer provide a bearing. Its line of position may be plot using GPX input. Two options:

• RDF onboard
• RDF on station

Fix by two RDF bearings with OpenCPN.